According to Eric Tannenbaum, executive producer on the show, Alan Harper is loosely based on his real life friend Stephen Deane. Alan is the only character who appears in every episode of the series.[1]

Alan lives a sad, miserable life of constant poverty, failure, rejection and surrounded by people who can't stand him and plain don't want him around. Alan used to be married to Judith, who is the mother of their child Jake. At some point, Judith and Alan divorced. Alan lost the majority of his belongings and most of his income is used in paying alimony and child support. Alan drives a Volvo station wagon and owns a chiropractic clinic in the San Fernando Valley. He gets disturbed when individuals call attention to the fact that he isn't a medicinal specialist. A main theme of the show is Alan and his housemate's contrasting abilities, including his brother's (and later, best friend's) success in dating. Alan is very awkward when it comes to women, and he has had several long-term relationships end badly. Charlie's housekeeper, Berta, described Alan as "the only man who can drive any woman out of Charlie's house." This theory was proven when Charlie was afraid of his attraction to Chelsea's gorgeous friend Gail, and falsely told Alan he had a shot with her; after Alan flirted with Gail, she fled the house in horror and Charlie's temptation was gone.

As a child, Alan was very intelligent and always got outstanding grades, but often the victim of bullying and got no help from Charlie since his brother participated in much of it. Not much is known about his relationship with their father since he died from food poisoning when they were young, after Evelyn served their father spoiled fish that had been stored in a drawer. Alan's relationship with Evelyn is active but stressful. Alan has expressed bitterness towards his mother's neglect during his childhood.

Alan drives a 2001 Volvo V70 station wagon, runs his own chiropractic-care clinic in the San Fernando Valley, and gets irritated when people point out that he's not a "real" doctor. He lives in the guest room of Charlie's house, for which he pays no rent to Charlie because all his money has gone toward alimony and care of Jake. When Evelyn offers to pay for Jake's college education, Alan loses his incentive to go to work and feels aimless. He then agrees to pay rent to Charlie. Alan has also had to endure whatever inconvenience Charlie throws his way, and the fact that Charlie really wants him to move out permanently. Although Alan sometimes fantasizes about killing Charlie in his sleep, he is devastated when Charlie reportedly dies after being struck by a train.

While he loves his brother and son, Alan resents Charlie somewhat, mostly because everything just seems to fall into Charlie's lap, while Alan has worked hard his whole life only to remain a failure. (Alan notes at the beginning of Season 8 that just one of Charlie's monthly royalty checks for his children's songs is more than he makes in a year.) Although he and his brother do have a sometimes tense relationship, they remain loyal to one another with Charlie able to cheer Alan up when he needs it, or Alan having to control Charlie's free spending ways. He has little confidence in Jake, mostly because of his lazy, unmotivated attitude, but he does love his son.

Alan also gets little sympathy even when terrible misfortunes befall him, including the time he injured himself fixing a satellite dish on the roof, torments caused by Charlie's behavior, and his divorce from Kandi.

Generally a nice guy, Alan has displayed some bad behavior and sneaky motives. When Charlie attends couples-counseling with Chelsea, he fed Charlie false information from conversations with her. He has also hidden money from Charlie and refrains from telling Chelsea he was not Charlie when she snuggled next to him on the couch. Alan hits his low point when his above-board idea to solicit money from all his "family and Friends" in order to finance an ad campaign for his floundering chiropractic clinic becomes a Ponzi Scheme. This encourages him to let his dark side out, even though he ends up returning everyone's original investment.

Because of his cheapness, neurotic nature, and inept social skills, many find Alan annoying, even insufferable—-particularly Charlie, Evelyn, and Berta, who calls him "Zippy." On his 40th birthday, instead of saying nice things about him, everybody pointed out all his faults. Also, Jake seems to have little respect for him, though Jake is not particularly respectful of Charlie or Judith either, and is not generally rude when he talks to his dad. Though Evelyn has called him the good child, she added that Charlie had not set that bar very high. She also once seriously suggested he accept some prison time after an assault charge because she wanted to save money instead of using it to hire a lawyer. This leaves Alan with very few (If any) friends.

It is also implied that in the series that God himself has a dislike for Alan, for example when Charlie told Alan reminded him of Job, Alan shouts to the sky that he is not going to lose his faith only to start raining a few seconds later. The same thing happens in "Pie Hole, Herb" when Charlie refuses to take Alan back in (having kicked him out earlier), locking him out of house. Alan is also seen as pitiful when he tries activities such as model car building and puppetry, because it highlights his anemic social life.

Alan is a terrible liar, as proven in several episodes where he hastily creates a lie to get out of doing something, and Charlie always asks him for more detail to torture him and expose the lie.

Judith (Marin Hinkle) is Alan's first wife. She is also the mother of Jake Harper. Judith has divorced Alan, stating that it was a loveless marriage and later making claims that she became a lesbian. While both of them are shown arguing in front of Jake in the beginning of the series, it is later revealed that Judith instigated the divorce. She later demanded primary custody, child support, alimony,[2] and literally every penny of Alan's income. She also demands their house, causing Alan to move in with Charlie. Judith has appeared at Charlie's house demanding for more money for various expenses she claims cannot be paid with neither child support nor alimony. She is otherwise a housewife and stay-at-home parent. Judith appears to be a very determined feminist as well as a misandrist, but she seems to be happier in her second marriage. It is later revealed that Judith's antisocial behavior is not limited to misandry, as she has been cruel towards her sister and parents. Nevertheless, the episodes continue to show that she has continued to abuse Alan to the point of it becoming a comedicrunning gag.

The reason Alan and Judith became married in the first place is because both of them had a similar past. Both of them were extremely unpopular in school and neither of them had supportive families. Judith later developed an eating disorder and eventually expressed distrust in Alan as a result of her bitterness. She always finds an opportunity to take advantage of him. Before the divorce, Alan actually thought he and Judith were on their way to reconciliation until he was served divorce papers in the mail.

Usually bitter enemies with each other, there was one moment in Season 3 where Alan and Judith agreed that Alan should spend the night in Judith's bedroom again. Their attempts at intimacy are interrupted by Jake because they wanted to keep the "affair" a secret. After Judith's remarriage, Alan was unaware that he had not fully recovered from the divorce. He could not stop thinking about the new man with Judith every time Alan attempted to sleep with a new woman.

Judith's second husband is Dr. Herb Melnick (a "real" doctor, contributing to the insult towards Alan's occupation). (He was called Greg Melnick in earlier episodes.) Once Judith remarries, Alan becomes overjoyed at the prospecting of not having to pay anymore alimony that he made a cardboard check for his last payment. However, Alan continues to pay child support, which Judith does not need but gladly takes from Alan to keep him miserable.

She is generally portrayed as humorless, bitter, and hypocritical. Judith told Alan that the reason they were separating was because it was not working out, but then later told Alan that she had realized she was a lesbian, only to change her mind again later. While she sees herself as lonely and long suffering, Judith is actually quite cruel, spiteful, vindictive, irrational, unfriendly, and selfish. According to Alan, Judith was a thin, scared, needy and neurotic mess with a strange eating disorder when he met her, and lived in the shadow of her more attractive popular sister. This could explain why she grew into such a bitter, angry, hate-filled person.

Alan and Judith met as teenagers and married young, though Charlie and "everybody else" advised Alan against marrying Judith. He lost his virginity to her during an Aerosmith song (from the episode "Who Is This Vod Kanockers?"). During the separation, Alan desperately tried to reunite with Judith, not realizing that the real reason she kept calling him and asking him to rush over was simply to keep him doing the chores he always did around their home. Judith clearly depises him and takes every chance to make his life miserable, even though it is sometimes clear that Alan and Judith still have feelings for each other. Once she said: "I disliked you when we were married, I resented you when we divorced, but I don't think I hated you until you started having sex with that gorgeous, 22-year-old dumbbell."[citation needed] Judith also felt sorry for Alan after his second divorce to Kandi, though she made it clear that she would not give him any breaks on alimony even if he had to pay that to Kandi as well. (She also arranged for the lawyer who decimated Alan in their divorce settlement to represent Kandi, though it appeared that Alan's financial losses there occurred before Kandi left him.) In a Season 5 episode, Alan begins dating a divorced woman who is friends with him and Judith, but keeps having visions of Judith and Herb having sexual intercourse, when the divorced woman mentions that Judith told her that Herb was the "best she ever had!", leading his date to say that he's not over Judith. Alan and Judith tried dating again in Season 3, which was after the divorce, but their attempts at intimacy were always interrupted by Jake approaching and Alan having to hide. Then when they finally had some uninterrupted time alone, Alan got upset because Judith had learned some "new moves." As they fight about this, Jake approaches and Alan jumps out the second-story window and lands in a thorny bush. At home, he finally realizes that he and Judith do not belong together.

One time (though it might have been intended as a joke to the audience), it was strongly implied that Jake might not be Alan's son, since he bears a strong resemblance to three long time acquaintances of Judith and Alan who were all in dead-end jobs (exterminator, water man and postman). While it was probably a joke, given Judith's attitude towards Alan, it's not an unlikely scenario. However given Jake's recent misfortunes with girls, he seems destined to have his father's luck.

Alan has even tried to be friends with Judith; however, it was extremely difficult for him to be happy for the woman who ruined his life.

Judith has accused Alan of being controlling, even though she dominated the marriage while Alan bent over backwards trying to make her happy. Her relationships with her parents and sister are not much better; her mother is a longtime alcoholic and prescription pill abuser; she's called both parents "poison"; and she argues with her sister constantly. Judith has little tolerance for people she does not like; she was cruel to her future sister-in-law; and her first words whenever Alan comes to her house are "What are you doing here?"

During the divorce proceedings, Alan has suffered greatly. He lost most of his possessions after Charlie slept with his attorney (Heather Locklear), then broke up with her, forcing him to fire her before the settlement could be finalized. Even after the divorce, Alan is constantly at Judith's mercy because of her powerful lawyer. Judith gets remarried in "Smooth as a Ken Doll" to Dr. Herb Melnick, Jake's pediatrician.[3] Since that day, Alan may only be paying alimony to his second wife Kandi, a relief since there was some time before Judith remarried that he had to pay it to both Judith and Kandi. It is possible Alan does not pay Kandi alimony because she now makes much more money than he does, and that she signed divorce papers because she wanted to safeguard her earnings from Alan.

While Judith blames Alan and Charlie for a lot of Jake's shortcomings, she herself seems to have little faith in him and far less patience, as she takes any chance she can to drop him with Alan at Charlie's house. In Jake's Final Episode, Jake told Alan the divorce was never his fault and all Judith's. This showed that even her own son couldn't deny she was a hopelessly miserable woman.

In Season 6, Judith threw Herb out of their house and later slept with Alan, but their reconciliation ended when Alan realized Judith was the same angry, irrational person who had divorced him. Judith later told Alan that she and Herb were expecting a child, leaving a horrified Alan to think he might be the biological father. Judith stated that Herb was the father and threatened to kill Alan if he revealed their affair. Judith does not like the fact that her daughter looks just like Alan, but Alan seems to enjoy pointing it out to her.

Despite saying she loves Herb, Judith seems to treat him in the same cruel and unfair way she treated Alan. Judith's parents seem to prefer Alan to Herb although Herb is a "real" doctor — but they also prefer Alan over Judith. Herb and Alan are great friends, but Judith disapproves, so Herb has to lie to her in order to hang out with Alan and/or Charlie. Over the course of the show, Alan and Judith's mutual hatred increases to the point that one will do anything to upset the other. When he could not afford a nice birthday present for his girlfriend Lyndsey, Alan stole earrings from Judith's house that he'd gotten for her when they were married, and after getting away with it, he decided to steal a nice necklace from Judith as well.

Alan's second ex-wife Kandi (April Bowlby) was one of Charlie's former girlfriends, whom Charlie originally dated as a backup in case something went wrong between him and his girlfriend Mia.[4] When Kandi came looking for Charlie, who was now more serious about Mia, she met Alan and they fell in love. They married in Las Vegas, shortly before Alan won $500,000. They divorced later, initially because Alan did not want another child.[5] In the divorce, she received the condominium they bought with the casino winnings.

When Alan changed his mind and decided that he wanted to have children with Kandi, they had not officially signed their divorce papers. Kandi then heard that she had a main role on the TV series Stiffs and said that "nobody wants to see a pregnant 'forensic' investigator"[5] before signing the papers that ended their marriage. Their married life was never shown in episodes, inferred to have lasted only between the end of the third season and beginning of the fourth. Early in Season 4 Alan noted that after they bought a condominium, Kandi squandered their remaining Vegas winnings on clothes and shoes. Alan briefly mentioned Kandi in Episode 5 of Season 4 when he tells Charlie that he is paying alimony to two ex-wives. She was not seen or mentioned in Seasons 5–9. When Alan is given the opportunity to talk about his two divorces to Charlie in Season 7's "Captain Terry's Spray-On Hair," he only mentioned his life with Judith. Since Charlie is upset about learning he has not been satisfying Chelsea like he thought he was, and is asking for Alan's advice since Alan is an expert at not satisfying women, it can be inferred that Alan at least had a very happy sex life with Kandi. Kandi returned in the season 10 episode, "I Scream When I Pee", wanting Alan back, but he turned her down for Lyndsey. Lyndsey was happy that Alan chose her, but when Kandi called Alan in the middle of the night, pretending to be suicidal, she came on to him, and paparazzi took photos, which Lyndsey saw. Alan pleaded with Lyndsey that nothing happened, but she didn't believe him. Kandi went to Lyndsey's house and explained everything. Kandi and Lyndsey ended up sleeping together, and agreed Alan must never find out. Walden was shocked that Kandi and Alan were married, and despite being a big fan of Kandi, Alan didn't introduce him to her. Alan and Kandi also did not discuss Charlie's death, despite Charlie being the one who introduced them.

After Charlie Harper's apparent death (due to the departure of Charlie Sheen), Walden Schmidt moved into his house to maintain "Two and a Half Men" living together. For a very short time, Alan became married to Walden. They adopt a precocious African-American child, Louis, played by Edan Alexander.

Alan has a brother named Charlie. Charlie is a musician, spending very little time at his piano writing jingles for commercials as well as theme songs for television. Charlie was kind enough to let Alan move into his house without forcing rent. He completely understands the financial situation with Alan's divorce. Charlie has also expressed dislike towards Judith. However, Alan's privileges are severely limited. Charlie has stated that the restrictions would be lifted if Alan starts paying rent, which of course he is unable to do so.

Charlie's carefree life came to an end, apparently during season 9. It is then revealed that Charlie was cremated. At Charlie's funeral, Alan is the only person who tries to say something positive about his brother. Berta is also one of the very few to have expressed any sadness towards the loss of Charlie. Evelyn is also upset but quickly focuses on Charlie's House. Alan said that the house was given to them in the will. Adding to Alan's long list of misfortune, Evelyn said that Charlie's house was not paid off. In fact, he had three mortgages, which means that Alan would never be able to pay for the house. Evelyn later claimed that it would be impossible for Alan to find a buyer by himself and that Alan could never afford Evelyn's inflated commission. Alan had a final moment alone with Charlie, but then spilled Charlie's ashes once he stumbled upon Walden who attempted suicide after divorce. Fortunately for Alan, Walden is a billionaire needing a new home and Charlie's house is sold to Walden. Alan and Jake are invited to stay at this house after Alan saves Walden from financial ruin. This keeps the status of there is "Two and a Half Men" in that house.

Walden ended up donating Charlie's piano to a music school, causing Alan to have an emotional and mental breakdown, which progresses to the point where he comes to believe he is actually Charlie. Alan was later sent to a "relaxation facility".

It is later revealed that Charlie did not die, but was finally kidnapped by Rose. He remained captive for years until the series finale, when he escaped with the intention of killing Alan, Walden, and Evelyn, but was killed by a falling piano right before he could enter the house.

In the season 11 premiere, Charlie's illegitimate daughter Jenny appears looking for her uncle, and displays traits of her father, much to the delight of Evelyn and Berta, but to the frustration of Alan. Alan is annoyed to learn that Jenny got big checks from Charlie every month, even though he never lent a penny to his brother.

Another recurring theme for Alan is that he is constantly stricken with extreme misfortune, mostly caused by himself or Charlie's behavior. This is a cause for his neurotic personality. His misfortune usually revolve around women and money. Alan's poor luck was taken to the extreme in "Frodo's Headshots", where he found out Jake had impregnated his girlfriend, had Walden reveal to Herb that Alan is the father of Judith's daughter Millie, learned that Walden had begun dating Alan's ex-girlfriend Lyndsey while he was at a mental health clinic, got hit with an IRS audit, was told by Walden that he had to move out due to the awkwardness of him being around Lyndsey, failed at a suicide attempt, was molested by a male truck driver, turned away in the rain by his own mother, and was shot to death by Herb at the storage facility where Walden and Lyndsey had moved all of his stuff. While the closing scenes revealed that all of those events happened in a dream, Alan decided afterwards that in any realm of his life, happiness wasn't in the cards for him. Eventually in "Why We Gave Up Women", Alan had a heart attack when told by Walden he can't move back in, although a variety of events (ranging from residual sympathy for his plight to Walden's marriage proposal to Zoey being rejected) have allowed him to keep living there anyway as Walden desperately needed a friend.

When Walden first begins dating Zoey, he removes his expensive wedding ring and gives it to Alan; while it appears at first that the perennially destitute Alan has pawned the ring to pay his debts, he keeps it and gives it back to Walden when Walden requests it, only to watch in horror as Walden then throws the ring into the ocean. Walden says he would give Alan money, but Alan decides that he will keep living at the house and maintain the illusion that not taking money from Walden will keep some of his dignity intact.

A major point of humor regarding Alan in the series is that he is notoriously cheap. Many of Charlie's insults and jibes at Alan were usually references to his unwillingness to make the slightest expenditure. He gets his hair cut at a barber college, sneaks deviled eggs into the movies, and tries to avoid checks in restaurants by going to the bathroom when it arrives, leading Charlie to call it "the little cheap bastard's room". In one episode, Charlie joined him in the men's room to make sure he returns and pays his half of a check; Alan procrastinates so long that their ladies and the check were picked up by Geraldo Rivera. He finds out in the same episode that Alan's constant scrounging was a result of him saving every spare dollar he had for his lonely future as "Old Alan," and he had accumulated over $5,000 in cash.

In later seasons, his tightness becomes even more apparent, despite the fact that his financial situation seems to have improved on paper (he no longer pays alimony, Evelyn pledged that she would cover all of the expenses if Jake miraculously got into college, and he remains a rent-free resident at the beach house). When Alan pays for a meal for himself, Jake and Charlie, Charlie is so astonished that he photographs the event and comments on Alan's wallet opening for the first time.

In one episode, while at the movies, Alan orders $25 worth of food for Jake, only to tell Charlie that he "forgot" his wallet. This leads to an argument where Charlie complains that Alan said he would pay for parking, which he is unable to do, because he does not have his wallet. After a line builds up because of their arguing, Charlie agrees to pay the bill, as soon as Charlie brings out his wallet, Alan orders a bagel-dog to "make it an even $30". In season 9, Alan does exactly the same thing to Walden when they go to the movies.

When Melissa refuses to return to Charlie's house after Chelsea calls her a tramp for sleeping with Charlie, Alan resorts to dogging as he refuses to pay for a hotel. Melissa leaves angrily to walk home, commenting that it was not far considering Alan did not want to waste gasoline. (Alan revealed in "I Found Your Mustache" that he fuels up with $3 worth of gas at a time.)

In the episode "Pie Hole, Herb" Charlie borrowed $38 from Alan. Alan is so intent on getting every penny back that he resorts to stealing gasoline from Charlie's car. But since there was not enough gas in the tank, Alan points out that Charlie still owes him $24.78.

In "Sir Lancelot's Litter Box", Charlie bribes Alan at first with $20 to make him shut up about his relationship with Chelsea. When he still won't leave, Charlie gives him $40 which Alan initially takes but returns a few seconds later, only for Charlie to point out that he only gave back a $20 bill instead of the $40.

In the season eight episode "Skunk, Dog Crap and Ketchup" when Charlie and Lyndsey were having a night chat Lindsey stated that Alan was too cheap to pay for a prostitute.

Another reason for Alan's cheapness is that his chiroparactic practice has not been consistently successful. When Alan learned that an old friend and colleague living in the same area had a thriving one-man chiropractic clinic, he decided to emulate him by raising money for an advertising campaign, but ended up running a Ponzi scheme where all of his ill-gotten gains went towards luxury items for himself.

If Alan sees that anything on offer for free, he is usually very quick to be interested. When Chelsea's father takes Charlie out for drinks and exclaims that he's buying within earshot of Alan, he joins them despite not being invited initially. He also asks for Charlie to pay for drinks on his behalf when trying to charm a woman.

In Season 5's "Our Leather Gear is in the Guest Room," the episode begins with Alan and Jake coming home from clothes shopping, revealing that Alan buys Jake clothes that are far too big for him, saying that he will grow into them (believing that with Jake growing so much, regular clothes are a waste of money). Later in the episode, Alan and Charlie have a fight, resulting in Alan and Jake moving out. When they ask Evelyn if they can move in temporarily, Jake begins to say that Alan was too cheap for a hotel, before being interrupted by Alan.

In Season 8's "Lookin' for Japanese Subs," Jake attempts to produce a volcano effect in his mouth by swallowing a Mentos candy after drinking a can of Diet Coke. Jake's friend, Eldridge, points out that the drink is not the official Coca-Cola brand, with Jake replying, "Yeah, my dad did the shopping."

In Season 9's "Thank You for the Intercourse", when Alan begins behaving like Charlie he tells Jake to take his girlfriend out to dinner as his treat, but only gives Jake one dollar. Later in that episode, Jake tells Walden that Alan is behaving so much like Charlie that the only thing left of him is his cheapness.

In Season 9 episode "A Fishbowl Full of Glass Eyes," Walden gives Alan his wedding ring made of rhodium, and Alan goes to a pawn shop to see how much it's worth. Alan doesn't sell it even though it's worth at least seven digits (as he asks the clerk if the price was the clerk's phone number), out of respect for his friendship with Walden. When Walden throws it in the ocean, Alan waits for Walden to go back inside the house before diving into the ocean to look for it.

In Season 9's "Why We Gave Up Women", when it looks like Alan suffered a mild heart attack, he is taken to the hospital. When Walden tells the hospital receptionist that he wants Alan to have the best care possible and that he'll (Walden) cover it, the receptionist tells Walden, "You're gonna have to. This guy has the worst insurance policy I've ever seen. He's got a $500,000 deductible." One of Alan's worst moments of cheapness happens during the episode "Why We Gave Up Women". As he was having a heart attack, and Walden had dropped one hundred dollars, he crawled to it as he was having the heart attack.

Also in season 9, when Walden makes Alan a member of the board of his company Alan finally enjoys success, receiving a director's honorarium of $50,000 a year and Walden agrees to add Alan's name on the deed of the house.[6] Despite this improvement in his financial situation, Alan has continued with his "frugal" behavior.

In Season 11, when Alan is at the movies, he goes to the refreshment stand and asks for his free refill of soda. The employee says that is only allowed on the date of purchase and that the cup Alan's holding is a Finding Nemo cup. Alan also mentions that there was a spider in his popcorn and had to throw the whole thing away. Alan says he wants to speak to the manager when he has a chance and that Alan Harper wants to speak to him and that he knows him. The employee then tells Alan that they all know him.

In "Tucked, Taped and Gorgeous," Alan started to think about being gay himself after meeting a gay man named Greg in his single-parent support group. After meeting the man a couple of times, Alan got congratulated by most of his loved ones for finally "coming out." Alan found himself thinking this could be the reason he's had so many failed female relationships. Alan decides to kiss Greg to check if he is gay. When he tried to kiss Greg, however, Greg told him that Alan was definitely not gay, as he said he knows gay men... and that even if he was, "which you're not" he would state again, he does not find Alan attractive at all but finds Charlie "pretty." Alan jealously told Greg to get out of his car and drove away. Though relieved that he was not gay, Alan mentioned that he felt that "I was letting a lot of people down."[7]

In season 7, episode 5 "For the Sake of the Child", when a drunken Alan and Charlie are reading a relationship help book and get to a section where they must list things they have in common. Alan says that they both fight homosexual panic, but a furious look from Charlie says that only Alan does.

While packing Alan's belongings in season 8, episode 2, "A Bottle of Wine and a Jackhammer," Charlie sings a modified version of "Happy Days Are Here Again" into which he inserts the line, "I'm getting rid of the queer again," although this could be just a simple case of classic name-calling.

In season 8, episode 12, "Chocolate Diddlers or My Puppy's Dead", Charlie and Alan decide to eat ribs together and watch a movie. Alan says that they do not have to watch a movie because he had recorded Glee, leading Charlie to accuse him of being homosexual.

In Season 9, episode 6, Walden and Alan kiss (pretending to be gay) and Walden makes a comment "He claims to be straight but his lips opened a little when I kissed him."

In season 10, episode 1, Walden (drunk, and heartbroken over a breakup) suggests to Alan that they become gay and get married. Alan is completely on board because Walden is rich but Walden soon drops the idea. In season 12, however, Walden and Alan do marry but only so they can adopt a child together.

In season 10, episode 12, Walden is in a state of stress and confesses that he cannot get an erection. Alan says he can help, and after some uncomfortable hesitation, says he'll go brush his teeth. Walden then says he was talking about getting some kind of drug to help with the problem.

In season 11, episodes 9 and 10, Alan dates a transgender women named Paula who used to be a man named Paul.

In season 12 – the final season, Walden and Alan wed and pretend to be gay so Walden can adopt a baby. They later foster a six-year-old boy named Louis, and near the end of the season – they officially adopt him (though it appears that only Walden is Louis' parent, not Alan). In the series' penultimate episode, Walden and Alan divorce but keep their friendship intact.

Although he is more conscientious than Charlie regarding sex, Alan does display some sexual deviance. His pregnancy fetish is revealed in "Repeated Blows to His Unformed Head," when Berta's pregnant daughter Naomi (Sara Rue) visits and delivers. In that same episode, he tells Charlie that the best sex he and Judith ever had was while she was pregnant with Jake.

Throughout the series, Alan has a history of masturbating. In season 7 episode 5 "For the Sake of the Child," Alan tells Charlie that he masturbates angrily when he has trouble sleeping. In one episode, Charlie says that he caught Alan having sex with the vacuum, but Alan cites it as an "accident." Charlie says that accidents happen once, and he has caught Alan more than once. In the season 8 episode "Twanging Your Magic Clanger", Alan was watching porn movies in his bedroom naked when Charlie walked in. Later, Charlie finds Alan watching movies again naked, this time in his living room. Alan finally tells Charlie he has been masturbating because he wanted to use his prescription sexual enhancement pills before they expired. The next day, Charlie came home from a date with Michelle, and Alan was in his car listening to Mariachi music while masturbating. Later that night, Alan went to the movie theater and masturbated, which led to an arrest for exposing himself in public, and Charlie for once had the moral high ground when he ignored his brother's phone call begging to be bailed out of jail. In "Humiliation is a Visual Medium", when asked by Charlie how he copes with a lack of sex he responds "take up hobbies, work hard and yank it like a monkey in a mango tree."

He also uses Viagra, which his son Jake accidentally took. In episode 14 of season 8, "Lookin' for Japanese Subs," Charlie states that Alan threw his back out trying to pleasure himself. In season 8, one morning when Michelle asked Charlie about a noise she heard he answered that it was Alan masturbating and trying to fall asleep, this is also mentioned in the episode "Nice to Meet You, Walden Schmidt," Alan admitted he "masturbated and cried myself to sleep" while Walden was having sex with two women in Charlie's old bedroom. In "Slowly and in a Circular Fashion", when Walden's mother tried to bribe Alan with sex to vote Walden out of presidency of his company, Alan states "That won't work, I masturbated three times before I got here." It is learned in the episode, "Slowly and in a Circular Fashion" that he can perform auto-fellatio.